Im a great advocate for using salt treatments on goldfish before trying man made chemicals especially for fungus, ich and other parasites. Its a great tonic when used in small doses. I do not recommend keeping goldies in permanent saline solution though.
For me personally i use 1 level teaspoon per gallon to act as a stress reliever. 2 level teaspoons to help fight fungal diseases and help aid breathing and 3 for ich and other external parasites. Higher doses I use only as a bath or dip. Never ever use salt for any reason on fish less than 2 inches in body length.
These are my own personal preferences so please dont disrespect the methods i use...each to their own. Ive never had a problem using salt whereas ive lost fish using chemicals.